The telephone industry currently uses a non-portable numbering system based on the geographic location of the telephone. Currently, a telephone number comprises a three digit area code (NPA), a three digit switch number, and a four digit unique number on that switch. The area code is assigned based on a telephone's geographic location. For instance, Texas currently has eleven area codes assigned by geographic region and population: 210, 214, 281, 409, 512, 713, 806, 817, 903, 915, and 972. In the prior art, since a telephone number was assigned by the telephone's geographic location, a local call could be easily determined by a telephone system user based on the telephone numbers of the caller and the called party. If a telephone system user moved to a new geographic location, he/she had to have a new telephone number assigned.
Pursuant to requirements of the Telecommunications Act of 1996, local telephone carriers are required to provide local telephone number portability in the future. Local number portability refers to the ability of telephone customers to retain, at the same location, existing telephone numbers without impairment of quality, reliability, or convenience when switching from one carrier to another. Local number portability is a significant concern to potential competitors in the local telephone market because service provider portability will determine the practical ability of such providers to compete in the local market without offering very substantial discounts to persuade subscribers to switch to their service. True or universal telephone number portability will follow in the near future. True or universal number portability refers to the ability to have a telephone number that is not associated with a telephone user's geographic location. If a telephone system user with a true or universal portable telephone number moves to a new geographic location, he/she may keep the telephone number so long as both geographic locations are within the United States.
In the prior art, a non-portable telephone numbering system based on the geographic location of the telephone was used. A telephone system user could easily determine a local call based on the telephone numbers of the telephone system user and a called party since it was indicative of the geographic location of the telephone system user and the called party.
With phone number portability, it becomes apparent that the structure of a phone number, specifically the area code (NPA), will lose its geographical meaning. When a number is dialed, the telephone system user may have no idea whether this is going to be a long-distance call that is subject to toll charge because the portable dialed number will not provide any indication to the telephone system user of the geographic location of the called party. A telephone number with a different area code than that of the telephone system user may turn out to be a local call that is not subject to a toll charge. Whereas, a telephone number with the same area code and would be a local call today may belong to a customer thousands of miles away and thus turn out to be a long distance call.
The need for a toll charge and rate inquiry service prior to establishing a telephone call connection has become necessary with the future implementation of portable telephone numbers in the United States. There is thus an unmet need in the art for an automated telephone system to provide toll telephone charge information to a telephone system user using a portable telephone number.